The originals were manufactured by Bendix (not to be confused with the Bendix aftermarket that sells brake parts now, AFAIK everything the current Bendix sells is just other manufacturers product they put in their labeled boxes to sell to their customers). There are several casting numbers found on original Bendix master cylinders. The 2660809 casting number shown in a previous post along with 2225601 are the 2 most commonly found Bendix casting numbers found on these master cylinders, however I've also seen some that just have the letters "AANF" cast on the bottom.
